NFSv4: Add some support for case insensitive filesystems

Add capabilities to allow the NFS client to recognise when it is dealing
with case insensitive and case preserving filesystems.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/nfs4proc.c

@@ -3840,7 +3840,9 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
 		     FATTR4_WORD0_FH_EXPIRE_TYPE |
 		     FATTR4_WORD0_LINK_SUPPORT |
 		     FATTR4_WORD0_SYMLINK_SUPPORT |
-		     FATTR4_WORD0_ACLSUPPORT;
+		     FATTR4_WORD0_ACLSUPPORT |
+		     FATTR4_WORD0_CASE_INSENSITIVE |
+		     FATTR4_WORD0_CASE_PRESERVING;
 	if (minorversion)
 		bitmask[2] = FATTR4_WORD2_SUPPATTR_EXCLCREAT;
 
@@ -3869,6 +3871,10 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f
 			server->caps |= NFS_CAP_HARDLINKS;
 		if (res.has_symlinks != 0)
 			server->caps |= NFS_CAP_SYMLINKS;
+		if (res.case_insensitive)
+			server->caps |= NFS_CAP_CASE_INSENSITIVE;
+		if (res.case_preserving)
+			server->caps |= NFS_CAP_CASE_PRESERVING;
 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
 		if (res.attr_bitmask[2] & FATTR4_WORD2_SECURITY_LABEL)
 			server->caps |= NFS_CAP_SECURITY_LABEL;

fs/nfs/nfs4xdr.c

@@ -3533,6 +3533,42 @@ static int decode_attr_aclsupport(struct xdr_stream *xdr, uint32_t *bitmap, uint
 	return 0;
 }
 
+static int decode_attr_case_insensitive(struct xdr_stream *xdr, uint32_t *bitmap, uint32_t *res)
+{
+	__be32 *p;
+
+	*res = 0;
+	if (unlikely(bitmap[0] & (FATTR4_WORD0_CASE_INSENSITIVE - 1U)))
+		return -EIO;
+	if (likely(bitmap[0] & FATTR4_WORD0_CASE_INSENSITIVE)) {
+		p = xdr_inline_decode(xdr, 4);
+		if (unlikely(!p))
+			return -EIO;
+		*res = be32_to_cpup(p);
+		bitmap[0] &= ~FATTR4_WORD0_CASE_INSENSITIVE;
+	}
+	dprintk("%s: case_insensitive=%s\n", __func__, *res == 0 ? "false" : "true");
+	return 0;
+}
+
+static int decode_attr_case_preserving(struct xdr_stream *xdr, uint32_t *bitmap, uint32_t *res)
+{
+	__be32 *p;
+
+	*res = 0;
+	if (unlikely(bitmap[0] & (FATTR4_WORD0_CASE_PRESERVING - 1U)))
+		return -EIO;
+	if (likely(bitmap[0] & FATTR4_WORD0_CASE_PRESERVING)) {
+		p = xdr_inline_decode(xdr, 4);
+		if (unlikely(!p))
+			return -EIO;
+		*res = be32_to_cpup(p);
+		bitmap[0] &= ~FATTR4_WORD0_CASE_PRESERVING;
+	}
+	dprintk("%s: case_preserving=%s\n", __func__, *res == 0 ? "false" : "true");
+	return 0;
+}
+
 static int decode_attr_fileid(struct xdr_stream *xdr, uint32_t *bitmap, uint64_t *fileid)
 {
 	__be32 *p;
@@ -4413,6 +4449,10 @@ static int decode_server_caps(struct xdr_stream *xdr, struct nfs4_server_caps_re
 		goto xdr_error;
 	if ((status = decode_attr_aclsupport(xdr, bitmap, &res->acl_bitmask)) != 0)
 		goto xdr_error;
+	if ((status = decode_attr_case_insensitive(xdr, bitmap, &res->case_insensitive)) != 0)
+		goto xdr_error;
+	if ((status = decode_attr_case_preserving(xdr, bitmap, &res->case_preserving)) != 0)
+		goto xdr_error;
 	if ((status = decode_attr_exclcreat_supported(xdr, bitmap,
 				res->exclcreat_bitmask)) != 0)
 		goto xdr_error;

include/linux/nfs_fs_sb.h

@@ -271,6 +271,8 @@ struct nfs_server {
 #define NFS_CAP_ACLS		(1U << 3)
 #define NFS_CAP_ATOMIC_OPEN	(1U << 4)
 #define NFS_CAP_LGOPEN		(1U << 5)
+#define NFS_CAP_CASE_INSENSITIVE	(1U << 6)
+#define NFS_CAP_CASE_PRESERVING	(1U << 7)
 #define NFS_CAP_POSIX_LOCK	(1U << 14)
 #define NFS_CAP_UIDGID_NOMAP	(1U << 15)
 #define NFS_CAP_STATEID_NFSV41	(1U << 16)

include/linux/nfs_xdr.h

@@ -1194,6 +1194,8 @@ struct nfs4_server_caps_res {
 	u32				has_links;
 	u32				has_symlinks;
 	u32				fh_expire_type;
+	u32				case_insensitive;
+	u32				case_preserving;
 };
 
 #define NFS4_PATHNAME_MAXCOMPONENTS 512